At present, Freon refrigerants that have stable properties and are easy to be handled are used as refrigerants of an apparatus having a refrigeration cycle such as a freezer, a refrigerator, an air conditioner and the like.
However, although the Freon refrigerants have stable properties and are easy to be handled, it is said that the Freon refrigerants destroy the ozone layer, and since the Freon refrigerants adversely affect the global environment, the use of the Freon refrigerants will be entirely prohibited in the future after a preparatory period of time. Among the Freon refrigerants, hydro fluorocarbon (HFC) refrigerants do not seem to destroy the ozone layer, but they have properties to facilitate the global warming. Especially in Europe where the peoples are concerned about environmental problems, there is a tendency to prohibit the use of this refrigerant also. That is, there is a tendency that the use of the Freon refrigerants that are artificially produced is prohibited, and natural refrigerants such as hydrocarbon are used as in the past. However, such natural refrigerants are flammable, and limited resources must be used effectively, there is a problem that the amount of usage must be controlled.
Thereupon, the present invention has been accomplished by taking notice of refrigerants which melt into lubricant and which do not contribute to heat transfer, and it is an object of the invention to provide an apparatus having a refrigeration cycle in which the amount of refrigerant to be charged in the refrigeration cycle is reduced to enhance the safety.